A baker uses 3 cups of flour to make each cake. If f represents the total amount of flour, which equation models this situation?

A) f=3n, where n is 1 cake. 
B) f=3n, where n is the number of cakes. 
C) f=n/3, where n is the number of cups of flour in a cake. 
D) f=n/3, where n is the number of cakes.